The present invention relates generally to medical devices and methods and more particularly to devices and methods for sealing the lumen of a medical device for maintaining hemostasis (control of bleeding) attendant to the use of minimally invasive transluminal, endoluminal and other such devices and procedures wherein devices such as sheaths, through which other catheter devices are passed, are inserted percutaneously or surgically into a blood vessel of a patient, or in cases of laparoscopic procedures where sealing the lumen is to control the leakage of CO2 gas used to insufflate a body cavity.
Minimally invasive interventions have become increasingly popular for approaching a variety of diseases such as the diagnosis and treatment of coronary heart disease using stent devises, laparoscopic procedures in general surgery, neurovascular disease for implanting coils, stents and other procedures, venous disease for placing vena cava filters or other procedures, as well as treatment of abdominal aortic aneurysms using stent grafts that are placed in the aorta or other vessels. The sizes of the catheter devices used to perform these therapies can range from 3 French to 30 French (0.039xe2x80x3 to 0.393xe2x80x3). Typically the devices that are used are within a 7 to 24 French (0.066xe2x80x3 to 0.315xe2x80x3) diameter.
In procedures such as these, a device known as an access sheath, also known as an introducer sheath, is typically placed through the skin in the upper thigh area of a patient""s leg, either through a surgical cutdown or a percutaneous puncture, and down into the lumen of a blood vessel (vein or artery) with a technique known as the Seldinger technique (physician uses the xe2x80x9cflashbackxe2x80x9d or blood spurt to confirm that the center of the lumen has been reached by the device), once a sheath is placed, most procedures employ catheter devices that are then inserted through the sheath and into the blood vessel at some distance away from the intended treatment site, and are then advanced through the vessel lumen until the selected treatment location is reached. In most instances this approach is performed xe2x80x9cover the wirexe2x80x9d, a technique that requires the physician to first place a guidewire device through the sheath and into the vessel lumen over which the larger catheter device can be tracked to the remote location.
The access sheaths that are employed for initial entry into the vessel typically include an integral hemostasis valve of some kind on the proximal portion of the device. There are numerous designs, including xe2x80x9cduck-billxe2x80x9d type valves, valves that stretch and re-coil to accommodate various devices such as xe2x80x9cirisxe2x80x9d type valves, and various perforated elastomer valves. For example, U.S. Pat. No. 4,436,519 discloses a removable hemostasis valve having a xe2x80x9cduck billxe2x80x9d type construction. U.S. Pat. No. 5,685,858 discloses a sliding valve for use with a catheter when no sheath is used. U.S. Pat. No. 4,738,658 discloses a tapered valve for use when a sheath is removed. U.S. Pat. No. 5,423,762 discloses a modular catheter sheath introducer with a replaceable hemostasis valve. During a procedure, however, these valves can fail, leading to leakage around the catheter and the valve, resulting in increased blood loss.
Given the popularity of less invasive techniques and their success, a broad range of devices or varying diameters are being used through sheaths, and the procedures are becoming increasingly complex and time consuming, making hemostasis over the duration of the procedure of paramount importance. A common problem during these procedures is a xe2x80x9cleaky valvexe2x80x9d, or the inability to maintain hemostasis around the catheter or wire using the integral sheath valve. In many procedures using larger devices such as aortic stent grafting, leaking valves can be quite commonplace. Currently, some surgeons and interventionists (radiologists, cardiologists) resort to tying gauze strips around the leaking section in an attempt to stem the flow of leaking blood. Typically the gauze just absorbs the blood and does not provide a durable solution. Various attempts have been made to come up with an improved integrated valve to deal with these issues with limited success.
There is a need for improved ancillary devices and methods for more effectively maintaining hemostasis, often after the existing valves have degenerated during a procedure, either due to multiple catheter exchanges (a time during the procedure when no catheter is in place and only a guidewire remains in the sheath), or the use of large catheter devices such as during the placement of stent grafts (some up to 32 French). It would be desirable to have an ancillary device that allows a physician to quickly regain hemostasis during the procedure thereby minimizing blood loss, while still being able to pass additional devices through the indwelling sheath once the ancillary device is placed, and complete the procedure as intended.
It would be desirable to have a device that can be applied to an existing sheath device to provide axial compression along the shaft of the sheath device and radial pressure around any devices introduced through the sheath, to block any leakage that may be flowing from the compromised valve at the proximal end of the sheath. Such a device would need to accommodate a guidewire and other catheters to pass through it so that the procedure can be completed. In addition, it would be desirable for such a compression device to be fixedly connected to said sheath during the time when hemostasis is desired, but also be removable from the sheath device in the event that the sheath is removed or changed during the procedure, or is no longer necessary.
Furthermore, it would be desirable to have a system of devices and methods that are easily applied around an indwelling sheath, either by the physician or the assisting staff, and that do not add unacceptable bulk to the catheter body already in place against the patient""s skin. It is desirable that such improved devices be cost effective and adaptable to accommodate various sheath sizes, while still allowing the physician to pass additional catheters and instruments through the ancillary devices while continuing to minimize blood loss.
It would be further desirable to apply the compression device of the present invention to achieve hemostasis without requiring the removal of any indwelling instrumentation (such as catheters and guidewires), or having to thread such compression device over the entire length of the indwelling instrumentation to reach the desired point of hemostasis.
These and further objectives and advantages are met by the design and use of the various embodiments of the present invention. The present invention provides for improved methods and apparatus for providing a seal around a primary treatment device, such as, for example, regaining hemostasis during an intraluminal procedure when the primary means of hemostasis is compromised or fails, or in the case of laproscopic procedures, to control leakage of gas used to insufflate a body cavity. For purposes of this specification, the terms xe2x80x9cstandard introducer sheathxe2x80x9d or xe2x80x9ccatheterxe2x80x9d, or xe2x80x9cintegral valvexe2x80x9d, xe2x80x9claparoscopic trocar or portxe2x80x9d or xe2x80x9cguidewirexe2x80x9d shall all refer to primary treatment devices that have been placed in the patient prior to a medical procedure or during the procedure, usually endoluminally or percutaneously. Usually a standard introducer sheath will have an integral valve or elastic orifice at the proximal end to aid in hemostasis, but still allow the passage of therapeutic or diagnostic devices therethrough. In some instances, a sheath is not used, and therefore the therapeutic device may be a primary treatment device itself, such as a catheter with a valve. It should be noted however, that in the case of a procedure performed without a sheath the device of the present invention may be applied as the primary means of sealing by way of attachment around the proximal portion of the treatment device, such as a laparoscopic trocar or an endoluminal stent graft delivery device.
To achieve such sealing, the invention provides for a compressible, resilient plug that is adapted for positioning at the proximal end of a sheath device, i.e., an introducer sheath or other primary treatment device described above. The plug includes a slit extending longitudinally of the plug and opening to an outer surface of the plug in order to receive a therapeutic or diagnostic device, such as a catheter, guidewire, trocar, etc., that is operationally passed through the sheath device. The invention further provides means for compressing the plug, thereby providing axial pressure against the sheath device as well as radial inward pressure against the therapeutic or diagnostic device to maintain a seal and minimize leakage from the sheath device.
In particular, in a first embodiment of the present invention a compression device is provided having a rear hub and a front hub adapted to be placed around the shaft of a standard introducer sheath proximal end. The front hub and rear hub are operatively connected to two or more ratchet projections extending from one or other of the hubs, and adapted to be engaged into slots housed on the other hub. The compression device is preferably formed in a substantially cylindrical configuration having a longitudinal opening at some point around the circumference of the device for receiving the shaft of a standard catheter device from a sideloading position. The front hub preferably has at least two receiving slots formed in the sidewall thereof and defined further by release tab members extending therefrom. The rear hub includes two or more longitudinal projecting elements adapted for mating engagement with the front hub receiving slots. The rear hub further comprises a housing to receive a compression plug valve of the present invention.
In an alternate embodiment of the present invention, the compression device has a single ratchet mechanism. The combination of the front and rear hub is achieved by interlocking a ratcheting member shaft adapted to extend longitudinally from the front hub, and a corresponding ratchet member shaft extending longitudinally from the rear hub, said rear hub further having a through hole at the base of the rear hub, to receive the shaft of the front hub ratchet member.
In a further alternate embodiment of the present invention, the front and rear hub matingly engage upon insertion of the front hub into the cylinder of the rear hub (or vice versa), each hub including a threaded surface on either the inside or outside of the cylinder of the hub, depending on which one is to be inserted into the other.
In a further alternate embodiment, the compression device of the present embodiment is configured in the arrangement of a side-loading clamp, having a front portion and a rear portion and adapted to fit over the proximal end of a standard sheath and integral hemostasis device. This embodiment includes a front clamp to stabilize the compression device around the shaft of the standard introducer sheath or catheter, and an independently operating rear clamp having a housing for a compression plug, once the rear clamp is placed around the proximal portion of the introducer sheath and up against the integral valve, the compression plug operates to seal off any leakage.
In an exemplary use of the present invention, upon noticing that the hemostasis valve of the standard sheath (inserted in the patient) has begun to leak, a physician or assisting staff member will take the compression device of the present invention and place the introducer sheath catheter shaft and the proximal portion of the introducer sheath (usually valve end) into the longitudinal openings of the front and rear hub of the present invention, respectively (e.g. side loading the catheter shaft into the compression device). The operator will then operate the compression device of the present invention to engage the front and rear hub, bringing the compression pad of the present invention into contact with the leaking end of the introducer sheath, thereby applying axial pressure along the shaft of the introducer sheath and compressing radially around any device inserted therethrough, and abating any fluid flow from the sheath valve. The rear hub and compression device are adapted to receive a guidewire and other devices and therefore, the medical procedure already in process may then resume through the existing introducer sheath and the compression device of the present invention.